Method for assembling a mechatronics sensor

ABSTRACT

A method of mounting a mechatronics control module ( 14 ) includes an electronic control unit ( 16 ) having a flex foil circuit ( 34 ) with a multiple of mounted electronic components including sensors ( 24 ) which sense the hydraulic state of the transmission clutch or other frictional engagement elements within the transmission system. The sensor is mounted to a base plate ( 82 ) which is mounted to a fixture ( 88 ) which folds the flap ( 84. ) When the base plate ( 82 ) and mounted sensor are removed from the fixture ( 88 ), the flap ( 84 ) unfolds so that the circuit traces of the flex foil ( 34 ) are adjacent the contacts ( 94. ) In a final step, the circuit traces ( 81 ) are electrically connected to the contacts ( 94. )

The present application claims priority to U.S. Provisional PatentApplication Ser. Nos. 60/255,941, filed Dec. 15, 2000; 60/255,942, filedDec. 15, 2000; 60/255,943, filed Dec. 15, 2000; 60/255,944, filed Dec.15, 2000; and 60/255,945, filed Dec. 15, 2000.

BACKGROUND OF THE INVENTION

The present invention relates to an attachment arrangement, and moreparticularly to an attachment arrangement for components mounting withina vehicle transmission.

A hydraulically operated vehicle transmission is typically equipped withmultiple frictional engaging elements such as hydraulic clutches, disks,brakes and the like that are engaged and disengaged bysupplying/discharging operating oil to/from the frictional engagingelements. Proper operation and timing of the shift is achieved byoptimizing the oil pressure for engagement/disengagement. The detectionof the state of the clutch or other such frictional engagement elementsis typically achieved by detecting the engaging oil pressure through anoil pressure sensor. The oil pressure sensor communicates with atransmission electronic control unit which commands the gear shittiming.

Ordinarily, the sensor is located within the transmission case whichsubjects the sensor to an extremely difficult environment. As a result,these components must be connected in a manner which is robust andimpervious to the environment within the transmission case. Typically,multiple wire harnesses connect individual sensors to a connectorextending through the transmission case. An external wire harness thenprovides communication between the sensors and the transmissionelectronic control unit. Only the sensors and their wire connections arelocated within the transmission case to avoid subjecting the electroniccontrol unit to the difficult environment within the transmission case.Disadvantageously, the wire connections must routed within thetransmission case to avoid multiple moving transmission components. Inaddition to the weight penalty of multiple wire harnesses, the routingmay become rather complex and multiple wire connections may increase thepossibility of failure.

Accordingly, it is desirable to provide a compact mounting arrangementfor sensors and associated components which are resistant to theenvironment within a transmission case while minimizing wire connectionsand providing advantageous assembly versatility.

SUMMARY OF THE INVENTION

The transmission system according to the present invention provides atransmission housing having a mechatronics control module mountedtherein. The mechatronics control module includes an electronic controlunit having a flex foil circuit for the mounting of multiple electroniccomponents including sensors which sense the hydraulic state of elementswithin the transmission system.

One embodiment of a method for mounting the sensor includes laminatingthe flex foil to a base plate such that the circuit traces are locatedopposite the base plate. A flex foil flap which was previously cut intothe flex foil is aligned adjacent to an opening in the base plate.

A fixture having an extension is aligned with the opening and folds theflap such that flap is pushed substantially perpendicular to theopening. The sensor is mounted to the base plate such that the contactswhich extends from the sensor, clears the folded flap and are receivedwithin a recess in the fixture. The base plate and mounted sensor areremoved from the fixture and the flap unfolds so that the circuit tracesof the flex foil are now adjacent the contacts. In a final step, thecircuit traces are electrically connected to the contacts by laserwelding or the like.

The present invention therefore provides a compact mounting arrangementfor sensors and associated components which are resistant to theenvironment within a transmission case, minimize wire connections, andprovide extensive assembly versatility.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of this invention will becomeapparent to those skilled in the art from the following detaileddescription of the currently preferred embodiment. The drawings thataccompany the detailed description can be briefly described as follows:

FIG. 1 is a general perspective view of a transmission system for usewith the present invention;

FIG. 2 is a sectional schematic view of a vehicle transmission housingincluding a sensor attachment arrangement according to the presentinvention;

FIG. 3A is a general exploded view of one sensor attachment arrangementaccording to the present invention;

FIG. 3B is a general top perspective view of the sensor attachmentarrangement illustrated in FIG. 3A;

FIG. 3C is a general bottom perspective view of the sensor attachmentarrangement illustrated in FIG. 3A;

FIG. 4A is a general exploded view of another sensor attachmentarrangement according to the present invention;

FIG. 4B is an expanded view of a flex foil flap of the sensor attachmentarrangement illustrated in FIG. 4A;

FIG. 4C is a general bottom perspective view of the sensor attachmentarrangement illustrated in FIG. 4A;

FIG. 4D is a general top perspective view of the sensor attachmentarrangement illustrated in FIG. 4A;

FIG. 5A is a general exploded view of another sensor attachmentarrangement according to the present invention;

FIG. 5B is an expanded view of an extended flex foil portion attached tothe sensor illustrated in FIG. 5A;

FIG. 5C is a general top perspective view of the sensor attachmentarrangement illustrated in FIG. 5A;

FIG. 5D is a general bottom perspective view of the sensor attachmentarrangement illustrated in FIG. 5A;

FIG. 6A is a general exploded view of another sensor attachmentarrangement according to the present invention;

FIG. 6B is a general bottom perspective view of the sensor attachmentarrangement illustrated in FIG. 6A;

FIG. 6C is a partial sectional view of the sensor attachment arrangementillustrated in FIG. 6A;

FIG. 7A is a general exploded view of another sensor attachmentarrangement according to the present invention;

FIG. 7B is a general exploded view of the sensor attachment arrangementillustrated in FIG. 7A adjacent to a hydraulic control unit illustratedin FIG. 2;

FIG. 8 is a schematic representation of one sensor mounting methodaccording to the present invention; and

FIG. 9 is a schematic representation of another sensor mounting methodaccording to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 schematically illustrates a vehicle transmission system 10. Thetransmission system 10 includes a transmission housing 12 having amechatronics control module 14 mounted therein. The control module 14includes an electronic control unit 16 communicating to a vehiclecontroller 18 through a wire harness 20. The electronic control unit 16preferably include a flex foil circuit with a multiple of surfacemounted electronic components as will be further described below. Thewire harness 20 is connected to the control unit 16 through a connector22 that is mounted through the housing 12. Sensors 24 communicate withthe control unit 16 to provide the hydraulic state of the transmissionclutch or other frictional engagement elements (illustratedschematically at 26) within the transmission system 10.

Referring to FIG. 2, the electronic control unit 16 is preferablymounted to a base plate 28 which covers at least a portion of ahydraulic control unit 30 having a plurality of hydraulic channels 32(only one illustrated.) The electronic control unit 16 preferablycommunicates with the sensor 24′ and other electrical components througha flexible circuit or flex foil 34. The flex foil 34 is essentially aflexible circuit board which provides electronic communication betweenelectronic components through a multiple of circuit traces (FIG. 3A.)The flex foil 34 may be one sided flex foil or two sided flex foil—thatis, the flex foil includes circuit traces accessible from either one orboth sides.

A control module housing 36 is mounted to the plate 28 to seal theelectronic control unit 16 from the environmental conditions within thetransmission housing 12. The flex foil 34, being flat and thin, ispassed between the housing 36 and the base plate 28 to interconnectother electronic components such as the connector 22 that are locatedoutside the housing 36. Other routes and seals will also benefit fromthe flex foil 34 structure which provides improved sealingcharacteristics in comparison to a round wire.

The hydraulic control unit 30 is preferably a valve assembly whichreceives fluid communicating with the frictional elements 26 through thehydraulic channels 32. As is generally known, through the operation ofvarious valves and ports within the hydraulic channels 32, the hydrauliccontrol unit 30 provides the working pressure to operate the frictionelements and automatic controls to shift the transmission system 10.

The pressure of the fluid within the channel 32 is measured by sensors24 (FIG. 1) such as a pressure sensor 24′ which communicates with theelectronic control unit 16. The electronic control unit 16, throughpreprogrammed logic and in receipt of other data from communication withthe vehicle controller 18 (FIG. 1), assures that the transmission system10 is properly shifted in response to vehicle speed. It should beunderstood that although only one sensor 24′, one friction element andassociated channel 32 are illustrated in the disclosed embodiment, otherand/or additional sensors, channels, and frictional elements whichcommunicate with the electronic control unit 16 will also benefit fromthe present invention.

Referring to FIG. 3A, one embodiment of a sensor mounting arrangement isillustrated. The flex foil 34 a is preferably bonded to the base plate28 a such that a laminate structure is formed. The base plate 28 a islayered with the flex foil such that a plurality of circuit traces 38 aon the flex foil 34 a are located opposite the base plate 28 a. Itshould be understood that when reference is made to the circuit traceside of the flex foil, the circuit trace side is that side whichprovides contacts or access to the circuit traces for components thatare mounted thereto as the circuit traces may be laminated withinmultiple layers of the flex foil for protection thereof. The circuittraces 38 a are electrically located to communicate with a multiple ofrespective contacts 40 a extending from the position sensor 42 a throughsoldering, laser welding, riveting spring-loaded contacts or the like.Attachment members such as rivets 44 mount the sensor 42 a in an opening46 in the base plate 28 a and sandwich the flex foil there between (FIG.3B.) It should be understood that other attachment members such assnaps, threaded fasteners, pins or the like will also benefit from theinstant invention.

Referring to FIG. 3C, an opposite side (non-flex foil 34 a side) of thebase plate 28 a is illustrated. The position sensor 42 a extends atleast partially through the base plate 28 a such that a movable portion48 a of the sensor 42 a is accessible. The movable portion 48 a isconnected to movable member such as for example only, a shift input(illustrated schematically at 50 a) to sense the position thereof andcommunicate the sensed position to the electronic control unit 16 (FIG.2).

Referring to FIG. 4A, another embodiment of a sensor mountingarrangement is illustrated. The flex foil 34 b is preferably bonded tothe base plate 28 b such that a laminate structure is formed. That is,the base plate 28 b is layered with the flex foil such that a pluralityof circuit traces 38 b on the flex foil 34 b are located opposite thebase plate 28 b. Attachment members such as rivets 44 mount a positionsensor 42 b to the base plate 28 b on the side opposite the flex foil 34b.

A contact opening 52 within the base plate 28 b and flex foil 34 bexpose to the non-flex foil side of the base plate 28 b contacts 40 bextending from the position sensor 42 b. That is, the sensor 42 b ismounted such that the contacts 40 b face the non-circuit trace side ofthe flex foil 34 b. To allow communication between the circuit traces 38b and the contacts 40 b, a flex foil flap 54 is formed in the flex foil34 b adjacent the contact opening 52.

With reference to FIG. 4B, the flap 54 is folded over so that thecircuit traces 38 b are electrically attachable with the circuit traces38 b through soldering, laser welding or the like. The position sensor42 b is mounted to the base plate 28 b on the side opposite the flexfoil 34 b to expose a movable portion 48 b of the sensor 42 b (FIG. 4C.)Moreover, the circuit trace side of the flex foil 34 b is stillavailable to provide mounting area for additional electrical componentsdirectly opposite the sensor 42 b (FIG. 4D.) An extremely compactarrangement is thereby provided.

Referring to FIG. 5A, another embodiment of a sensor mountingarrangement is illustrated. The flex foil 34 c is preferably bonded tothe base plate 28 c such that a laminate structure is formed. In thisembodiment, an extended flex foil portion 56 extends beyond theperiphery of the base plate 28 c. That is, the base plate 28 c islayered with the flex foil 34 c such that a plurality of circuit traces38 c on the flex foil 34 c are located opposite the base plate 28 c.

A sensor 55 include a multiple of contacts 58 which are electricallyconnected to the circuit traces 38 c through soldering, laser welding orthe like. It should be understood that the contacts may include contactsof any size or shape. Preferably, one or more locators 60 extend fromthe sensor 55 on the same plane as the contacts 58 to be received intocorresponding alignment openings 62 in the flex foil apertures to assureproper alignment and contact between the contacts 58 and circuit traces38 c.

Referring to FIG. 5B, the sensor 55 is illustrated attached to theextended flex foil portion 56. Resilient retaining snaps 64 preferablyextend from the sensor 56. The extended flex foil portion 56 with theattached sensor 55 is folded over an edge (in the direction of arrow F)of the base plate 28 c. The retaining snaps 64 are inserted intocorresponding base plate slots 64′ to thereby lock the sensor 56 ontothe base plate (FIG. 5C.) The retaining snaps 64 preferably provide alocking surface 65 which engage the opposite side (Flex foil 34 c side)of the base plate 28 c (FIG. 5D). The sensor 56 is thereby mounted tothe base plate 28 c on the side opposite the flex foil 34 c and thecircuit trace side of the flex foil 34 c is again available to providemounting area for additional electrical components.

Referring to FIG. 6A, yet another embodiment of a sensor mountingarrangement is illustrated. The flex foil 34 d is preferably bonded to abase plate 28 d such that a laminate structure is formed. The base plate28 d is layered with the flex foil such that a plurality of circuittraces 38 d on the flex foil 34 d are located opposite the base plate 28d.

The base plate 28 d preferably includes a recessed area 66 for receiptof a sensor 68. The recessed area 66 defines a second plane P2 offsetfrom a first plane P1 defined by the base plate 28 d. The recessed area66 is preferably convex toward the laminated flex foil 34 d side and isdeep enough to receive the height of the sensor 68 (FIG. 6B.) A contactopening 70 in the base plate 28 d is located to allow receipt ofcontacts 73 extending from the sensor 68 on one side and a flex foilflap 74 from the opposite side. Preferably, the contact opening 70 islocated from the first plane P1 to the second plane P2. The flex foilflap 74 extends into the contact opening 70 in a cantilever manner (FIG.6C) when the flex foil 34 d is laminated to the base plate 28 d.

Referring to FIG. 6C, a partial sectional view of the installed sensor68 is illustrated. As described above, retaining snaps 72 are insertedinto corresponding base plate slots 72′ to thereby lock the sensor 68into the recessed area 66. Additionally, one or more locators 76 extendfrom the sensor 68 to be received into corresponding alignment openings78 in the base plate 28 d.

As the sensor 68 is mounted into the recessed area 66, the contacts 73are aligned with the contact opening 70 and are pushed past the flexfoil flap 74 to emerge on the opposite side thereof. That is, thecontacts 73 are passed to the circuit trace 38 d side of the flex foil34 d such that the contacts 73 extending from the sensor 68 areattachable thereto through soldering, laser welding or the like. Theflap 74 facilitates this passage. The sensor 68 is thereby mounted tothe recessed area 66 on the side opposite the flex foil 34 d andrecessed into the base plate 28 d. The recessed mounting provides manybase plate 28 d attachment advantages including improving the sealbetween the base plate and the hydraulic control unit (FIG. 2) tofurther minimize the possibility of leakage there between.

Referring to FIG. 7A, another embodiment of a sensor mountingarrangement is illustrated. The mounting arrangement illustrated in FIG.7A is similar to that disclosed in FIGS. 6A-6C, however, the sensor 68′is mounted to substantially flat base plate 28 d′. As illustrated inFIGS. 7B, this mounting arrangement provides for an advantageous sealbetween the between the base plate and the hydraulic control unit whichlocates the sensor 68′ directly adjacent pressure ports 75 in thehydraulic control unit 30 (also shown in FIG. 2). Accurate readings andan effective seal are thereby advantageously provided.

Referring to FIG. 8 a method for mounting the sensor as disclosed inFIGS. 6A-7B is disclosed. In a first step, the flex foil 80 is laminatedto a base plate 82 such that the circuit traces 81 are located oppositethe base plate 82. A flex foil flap 84 which was previously cut into theflex foil 80 is aligned with an opening 86 in the base plate 82.

In a second step, the flex foil laminated base plate 82 is located upona fixture 88. It should be understood that only a single sensor isdisclosed in the disclosed embodiment, a plurality of sensors arepreferably mounted simultaneously in a fixture which retains a multipleof base plates. The fixture 88 includes an extension 90 locatedsubstantially perpendicular to the fixture 88 which receives the baseplate 82. The extension 90 is aligned with the opening 86 and folds theflap 84 such that flap 84 is pushed substantially perpendicular to theopening 86.

In a third step, the sensor 92 is mounted to the base plate 82 by thedesired attachment members such as snaps, threaded fasteners, pins orthe like. Notably, the contacts 94 which extend from the sensor 92,clear the folded flap 84 and are received within a recess 96 in thefixture 88.

In a fourth step, the base plate 82 and mounted sensor 92 are removedfrom the fixture 88. As the base plate 82 is removed from the fixture88, the extension 90 lets the flap 84 unfold such that circuit traces 81of the flex foil 80 are now adjacent the contacts 94.

In a final step, the circuit traces 81 are electrically connected to thecontacts 94 by laser welding or the like. It should be understood thatthe welding or other attachment operation may be performed on this oranother welding dedicated fixture.

Referring to FIG. 9, another a method for mounting the sensor asdisclosed in FIGS. 6A-B is disclosed. The FIG. 9 method includesessentially the same steps as the FIG. 7 embodiment, however, a movableextension 90′ is provided. The fixture 88′ receives the laminated baseplate 82 and the extension 90′ folds the flap 84 substantiallyperpendicular to the opening 86.

The sensor is mounted to the base plate and then the extension 90′ isretracted. The flap 84 unfolds and the circuit traces 81 of the flexfoil 80 are adjacent the contacts 94. The circuit traces 81 are thenelectrically connected to the contacts 94 by laser welding or the like.

It should be understood that although sensors and connectors aredisclosed in the illustrated embodiment, other components will alsobenefit from the instant invention.

The foregoing description is exemplary rather than defined by thelimitations within. Many modifications and variations of the presentinvention are possible in light of the above teachings. The preferredembodiments of this invention have been disclosed, however, one ofordinary skill in the art would recognize that certain modificationswould come within the scope of this invention. It is, therefore, to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described. For thatreason the following claims should be studied to determine the truescope and content of this invention.

What is claimed is:
 1. A method of mounting an electrical componentcomprising the steps of: (1) attaching a flex foil to a base plate suchthat a flex foil flap comprising a circuit trace adjacent to a baseplate opening in said base plate; (2) deflecting the flex foil flap in afirst direction substantially perpendicular to said base plate; (3)passing an electrical contact of the electrical component into theopening in a second direction different than the first direction; (4)releasing said flex foil flap; and (5) electrically connecting saidcomprising a circuit trace upon said flex foil flap to said electricalcontact.
 2. The method as recited in claim 1, wherein said step (1)includes bonding the flex foil to the base plate.
 3. The method asrecited in claim 1, wherein said step (3) includes mounting a componenthaving the electrical contact to the base plate.
 4. The method asrecited in claim 3, wherein said step (3) includes riveting thecomponent to the base plate.
 5. The method as recited in claim 3,wherein said step (3) includes snapping the component to the base plate.6. The method as recited in claim 3, wherein said step (3) includesmounting the component to the base plate on a side of the base plateopposite the flex foil.
 7. The method as recited in claim 1, whereinsaid step (2) includes folding the flex foil flap opposite a directionfrom which the electrical component is mounted.
 8. The method as recitedin claim 1, wherein said step (1) includes locating the flex foil flapin a cantilever manner over the base plate opening.
 9. The method asrecited in claim 1, wherein said step (1) includes locating the flexfoil flap in a cantilever manner over an edge of the base plate opening.10. The method as recited in claim 1, wherein said step (1) includesfacing the circuit trace flex foil flap toward the base plate.
 11. Themethod as recited in claim 1, wherein said step (1) includes facing thecircuit trace flex foil flap away from the base plate.